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SHUTDOWN(2) System Calls Manual SHUTDOWN(2) NAME shutdown -- disable sends and/or receives on a socket LIBRARY Standard C Library (libc, -lc) SYNOPSIS #include <sys/types.h> #include <sys/socket.h> int shutdown(int s, int how); DESCRIPTION The shutdown() system call disables sends or receives on a socket. The how argument specifies the type of shutdown. Possible values are: SHUT_RD Further receives will be disallowed. SHUT_WR Further sends will be disallowed. This may cause actions spe- cific to the protocol family of the socket s to happen; see "IMPLEMENTATION NOTES". SHUT_RDWR Further sends and receives will be disallowed. Implies SHUT_WR. If the file descriptor s is associated with a SOCK_STREAM socket, all or part of the full-duplex connection will be shut down. IMPLEMENTATION NOTES The following protocol specific actions apply to the use of SHUT_WR (and potentially also SHUT_RDWR), based on the properties of the socket associ- ated with the file descriptor s. Domain Type Protocol Action PF_INET SOCK_DGRAM IPPROTO_SCTP Failure, as socket is not con- nected. PF_INET SOCK_DGRAM IPPROTO_UDP Failure, as socket is not con- nected. PF_INET SOCK_STREAM IPPROTO_SCTP Send queued data and tear down association. PF_INET SOCK_STREAM IPPROTO_TCP Send queued data, wait for ACK, then send FIN. PF_INET6 SOCK_DGRAM IPPROTO_SCTP Failure, as socket is not con- nected. PF_INET6 SOCK_DGRAM IPPROTO_UDP Failure, as socket is not con- nected. PF_INET6 SOCK_STREAM IPPROTO_SCTP Send queued data and tear down association. PF_INET6 SOCK_STREAM IPPROTO_TCP Send queued data, wait for ACK, then send FIN. RETURN VALUES The shutdown() function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error. ERRORS The shutdown() system call fails if: [EBADF] The s argument is not a valid file descriptor. [EINVAL] The how argument is invalid. [ENOTCONN] The s argument specifies a socket which is not con- nected. [ENOTSOCK] The s argument does not refer to a socket. SEE ALSO connect(2), socket(2), inet(4), inet6(4) STANDARDS The shutdown() system call is expected to comply with IEEE Std 1003.1g-2000 ("POSIX.1"), when finalized. HISTORY The shutdown() system call appeared in 4.2BSD. The SHUT_RD, SHUT_WR, and SHUT_RDWR constants appeared in IEEE Std 1003.1g-2000 ("POSIX.1"). AUTHORS This manual page was updated by Bruce M. Simpson <bms@FreeBSD.org> to re- flect how shutdown() behaves with PF_INET and PF_INET6 sockets. BUGS The ICMP "port unreachable" message should be generated in response to datagrams received on a local port to which s is bound after shutdown() is called. FreeBSD ports 15.quarterly July 27, 2015 SHUTDOWN(2)
NAME | LIBRARY | SYNOPSIS | DESCRIPTION | IMPLEMENTATION NOTES | RETURN VALUES | ERRORS | SEE ALSO | STANDARDS | HISTORY | AUTHORS | BUGS
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